List of top Irrigation and Drainage Engineering Questions

A salt affected crop field is to be leached with irrigation water having salt concentration of 3.5 meq/L. Salt concentration in saturation extract of soil is 15.2 meq/L. Leaching efficiency of field = 55%. In March, ET\(_0\) = 150 mm, effective rainfall = 75 mm, crop coefficient = 1.05. Find leaching requirement for the month in mm.

A 0.30 m well penetrates an unconfined aquifer (saturated depth = 40 m). Pumping 0.03 m\(^3\)/s for 8 hours. Drawdowns in two observation wells: 3 m at 20 m, 2 m at 50 m. Find drawdown in pumping well in m.

It is planned to provide irrigation in a crop field having field capacity and permanent wilting point of the soil as 0.21 cm\(^3\)/cm\(^3\) and 0.09 cm\(^3\)/cm\(^3\), respectively. The crop root zone depth is 0.90 m. The growing period of this crop is 1\(^\text{st}\) January to 31\(^\text{st}\) March, during which the observed reference evapotranspiration (ET\(_r\)), effective rainfall (P\(_e\)) and crop coefficients (K\(_c\)) are given: \[ \begin{array}{|c|c|c|c|} \hline \text{Month} & \text{ET}_r \, (\text{mm/day}) & P_e \, (\text{mm/month}) & K_c
\hline \text{January} & 11 & 8 & 0.80
\text{February} & 12 & 25 & 1.10
\text{March} & 14 & 27 & 1.15
\hline \end{array} \] Considering management allowable deficit (MAD) for this crop as 50%, the average irrigation interval during the growing period in days is:

A sprinkler irrigation system has been designed for a crop with the water application rate of \(1.17 \,\text{cm h}^{-1}\) and sprinkler discharge of \(1.3 \,\text{L s}^{-1}\). The coefficient of discharge and uniformity coefficient are 0.9 and 0.8, respectively. If the sprinkler spacing along the lateral is 20 m, the lateral spacing in m is

The average discharge, operating pressure and emitter constant of a drip emitter are \(4\,\text{L h}^{-1}\), \(110\,\text{kPa}\) and \(0.3\), respectively. The type of emitter is